Binary Tree Longest Consecutive Sequence III

我的问题：一开始我不会多叉树如何表示其子节点
list<TreeNode> children; root.children用来表示根的所有子节点
for (MultiTreeNode child : root.children)用来表示遍历root的所有子树

/**
 * Definition for a multi tree node.
 * public class MultiTreeNode {
 *     int val;
 *     List<TreeNode> children;
 *     MultiTreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    class ResultType{
        int maxLength, maxUp, maxDown;
        public ResultType(int maxLength, int maxUp, int maxDown){
            this.maxLength = maxLength;
            this.maxUp = maxUp;
            this.maxDown = maxDown;
        }
    }
    public int longestConsecutive3(MultiTreeNode root) {
        // Write your code here
        /**思路
         * 和Binary Tree Longest Consecutive Sequence II一样的做法。
         * II只要check一下left和right。
         * 这题因为有多个子节点，所以要用一个循环来check所有。*/
         if(root == null){
             return 0;
         }
         ResultType result = helper(root);
         return result.maxLength;
    }
    private ResultType helper(MultiTreeNode root){
        if(root == null){
            return new ResultType(0,0,0);
        }
        int up = 0;
        int down = 0;
        int maxlength = 0;
        //for循环check所有子树
        for(MultiTreeNode child : root.children){
        就和ii中 left = helper（root.left)一样，
        都要递归算出得到了以root孩子为根的子树，最大连续上升是多少，最大连续下降是多少
               ResultType childresult = helper(child);
               if(child.val + 1 == root.val){
                   up = Math.max(childresult.maxUp + 1, up);
               }
               if(child.val - 1 == root.val){
                   down = Math.max(childresult.maxDown + 1, down);
               }
               maxlength = Math.max(childresult.maxLength, maxlength);
        }
        maxlength = Math.max(maxlength,down + up + 1);
        return new ResultType(maxlength,up,down);
    }
}